<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    
</body>
<script>
    var a9=parseInt(prompt("请输入季节"))
    switch (a9) {
        case 3:
        case 4:
        case 5:
            document.write("春");
            break;
            
            case 6:
            case 7:
            case 8:
            document.write("夏");
            break;
           
            case 9:
            case 10:
            case 11:
            document.write("秋");
            break;

            case 12:
            case 1:
            case 2:
            document.write("冬");
            break;
        default:
        document.write("对不起请输入正确的年份")
            break;
    }
</script>
</html>